Mason Crane was overjoyed at claiming AB de Villiers as a maiden international wicket Getty Images

An impressive debut from Dawid Malan helped England seal the T20 series over South Africa with a 19-run victory at Cardiff.

Malan, the fourth England debutant in the series, contributed a classy 78 to help his new team cope with the absence of their captain, Eoin Morgan, and take the three-match series 2-1.

Morgan had decided to leave himself out in order to provide another opportunity for England to take a look at some of their fringe players. Specifically, he said they were keen to provide another game for Liam Livingstone, who endured a nervous debut at Taunton.

And while some ticket-holders were upset at the lack of star players in the England side - Joe Root, Ben Stokes and Moeen Ali were among those to be rested for this series, while Jonny Bairstow had returned to Yorkshire to prepare for the day-night Championship fixtures starting on Monday - Morgan's decision might have helped England build some depth ahead of a typically relentless winter schedule during which resources will be stretched.

Malan, in particular, took advantage in a strikingly assured performance. Having left his first ball outside off stump, he pulled his second - from the distinctly sharp Morne Morkel - for six to kick-start an innings that displayed timing, power and an ability to improvise. It was, by some distance, the highest score by an England player on T20I debut.

He was not the only new-ish player to impress. Mason Crane, back in the side after making his debut in Southampton, survived an early assault at the hands of AB de Villiers in a display that hinted at a wonderfully calm temperament. At one stage, de Villiers, who was playing his final match of the tour, swept Crane for 16 in three balls - two sixes and a four - but the young legspinner retained his nerve and his flight and, by the end of the over, had de Villiers well held by Alex Hales on the square-leg fence as he attempted a repeat. Crane, whose celebrations of his maiden international wicket were something to behold, finished his spell by conceding just two from his final over.

"He handled it really well," de Villiers said of Crane afterwards. "He was always the one to get after, but he stuck to his guns. Well played to him."

Livingstone, however, was unable to take advantage of his second outing. He would have been the man to miss out had Morgan played, and might have wished he had after falling first ball as he went across his stumps and attempted to scoop over the leg side.

There was also no debut for Craig Overton. Despite England having intimated that all their new faces would win an opportunity at some point during the series, Overton - who was declared fully sit - was not utilised. It left Somerset's director of cricket, Matt Maynard, unimpressed. He tweeted that he was "gutted" for Overton and then added "#brokenword".

"We couldn't get him in today," Morgan said. "We wanted to retain our seamers from the second game who bowled well. Craig is aware and all is fine."

Perhaps, had England failed to win, they would have been criticised for their decision to rotate to the extent they did. But with impressive performances over the series from the likes of Malan, Crane, Bairstow and Tom Curran, who again looked to have the skills and temperament to thrive at this level, England will feel it was a worthwhile experiment. It is probably also fair to suggest that, while both sides would have wanted to win this game, it was hardly the most meaningful confrontation either has played even this month. The calls for greater context for such matches are certain to increase.

"We recognise the series as a big opportunity to have a look at a younger group of players," Eoin Morgan told Sky Sports. "It's an important part of our development and our success in 50-over cricket and T20 has been down to the strength in depth we've had in the side. We've always had a lot of competition in the playing XI.

"Ideally, I would play, yes. Given the rotation system that we have had in the past, it's unfortunate. If it was a case where I could go on and captain, I would. But this is an important part of our development for this series. You have to look to the long-term."

Besides, Malan looked every inch an international-quality player. British-born but raised in South Africa, his debut has come relatively late - he is aged 29 - but he has put himself at the head of the queue of those pressing for places.

Here he added 105 in 63 balls with Hales, who survived a simple chance to Andile Phehlukwayo on 10, bringing up his fifty with a beautifully-played scoop to the boundary off Imran Tahir, while a driven straight six off Morkel also caught the eye.

South Africa's fielding was oddly fallible, though. De Villiers reckoned they "gave away around 20 runs" which, considering the margin of defeat, was crucial. "We let ourselves down in the field," he said.

Once the pair were parted, England fell away against some excellent death bowling from South Africa. England managed only 54 from the final 39 balls of their innings, culminating in a spell where they lost five wickets for 14 runs from 13 balls against Dane Paterson, who was twice on a hat-trick, and Phehlukwayo.

But only for a moment, when de Villiers was partnered by JJ Smuts, did it appear South Africa might get close. With Liam Plunkett again bowling at sharp pace and gaining some assistance for his back-of-a-length bowling from the River Taff End, South Africa subsided to 91 for 6 in the 14th over.

Phehlukwayo and Mangaliso Mosehle narrowed the margin with some impressive strokeplay - Willey was plundered for 34 from his final couple of overs - but once de Villiers had gone, there was only ever likely to be one result.